Is the research by Stanford University students who use logistic regression to predict sexual orientation from facial images really scientific?
One way to criticize the study could be to attack the data on which the study is based on. An image on a social network is not "neutral" (those are not ID photo) and certainly not images from a dating website (from which the data of the study come from).

For example as a homosexual / heterosexual person you will perhaps put forward different attributes on your photo (facial hair / glasses, type of clothes) to attract gender specific people. 

Those are parameters are not directly linked with the "facial profile" of the person but they will influence the black-box model during training, so you will end up thinking you can detect sexual orientation of a person with only his face characteristics but in reality your black-box algorithm have only detect a totally different characteristic (glasses for example) that are link with a specific sexual orientation.